<template>
  <div class="todo-footer">
    <label>
      <input type="checkbox" v-model="isAllCheck"/>
    </label>
    <span>
      <span>已完成{{completeSize}}</span> / 全部{{todos.length}}
    </span>
    <button class="btn btn-danger" v-show="completeSize" @click="clear">清除已完成任务</button>
  </div>
</template>

<script>
export default {
  name: 'TodoFooter',
  props: {
    todos: {
      type: Array,
      reqired: true
    },
    checkAllTodos: {
      type: Function,
      reqired: true
    },
    // clearCompleteTodos: {
    //   type: Function,
    //   reqired: true
    // },
  },

  computed: {
    completeSize () {
      return this.todos.reduce((pre, todo) => pre + (todo.completed?1:0), 0)
    },

    isAllCheck: {
      get () {
        return this.todos.length===this.completeSize && this.completeSize>0
      },

      set (value) { // value就是当前checkbox是否选中的标识值
        this.checkAllTodos(value)
      }
    }
  },

  methods: {
    clear () {
      console.log('TodoFooter', this)
      this.$emit('clearCompleteTodos')
    }
  }
}
</script>

<style scoped>
.todo-footer {
  height: 40px;
  line-height: 40px;
  padding-left: 6px;
  margin-top: 5px;
}

.todo-footer label {
  display: inline-block;
  margin-right: 20px;
  cursor: pointer;
}

.todo-footer button {
  float: right;
  margin-top: 5px;
}
</style>
